There is growing interest in the auto industry in controlling the position of the throttle valve using an electronic engine controller so as to optimize fuel consumption and engine performance. Vehicles employing a remotely operable throttle directly coupled to the vehicle accelerator pedal are frequently referred to as having drive-by-wire systems. The engine controller regulates the throttle position based on a number of inputs such as accelerator pedal position, engine speed, manifold pressure, etc. There are times, however, when it is desirable to reconnect the throttle valve to the accelerator pedal so that the throttle may be moved in a direct drive mode. A number of devices are known in the prior art for regulating the throttle position automatically using an electronic engine controller. U.S. Pat. No. 4,163,432, Hertfelder, discloses an electrically driven throttle actuator which is connected to the accelerator pedal via a releasable electric clutch. The throttle valve and accelerator pedal always remain mechanically coupled to one another.
U.S. Pat. No. 4,245,599, Des Laurres, relates to a vehicle idle speed control system having an adjustable throttle stop for idle speed control. The accelerator pedal always remains mechanically connected to the throttle valve.
U.S. Pat. No. 4,380,799, Allard, discloses a computer-based throttle position control mechanism. A mechanical linkage connects the accelerator pedal to the carburetor throttle valve. The effective length of the mechanical linkage may be varied by a servomotor, thereby regulating the throttle position.
U.S. Pat. No. 4,455,978, Atago, relates to an engine speed control system which employs an electric motor-driven stop so that the idle speed of the engine may be controlled.
U.S. Pat. No. 4,526,060, Watanabe, discloses an earlier system of the present inventor utilizing a throttle valve actuator providing a stop moved within two ranges to provide both idle speed control and vehicle speed control. During both modes the accelerator pedal remains constantly mechanically coupled to the throttle valve.
A feature of the present throttle valve actuator is its ability to automatically couple and uncouple the throttle valve from the accelerator pedal linkage in a specified relative orientation in response to a coupling signal so that the throttle may be controlled in either the remote drive or the direct drive mode.
Another feature of the present invention is that it provides a compact, reliable, cost-efficient throttle valve actuator suitable for use in the production of automobiles.
These and other features and advantages of the invention will be apparent upon further review of the description of the preferred embodiment.